USB Port to fuse box (add a fuse)

Ok..I’m at a loss here. I’ve tested all my wires, USB power off battery directly. I ground black, tie red into an add a fuse and plug into ACC fuse with (2) 7.5 amp fuses. Nothing ‍♂️ I switched the prongs of add a fuse…nothing. The power comes in from top leg of fuse so the load side of the add a fuse was correct the first time. What could be the issue/solution?
*Note- I do not want to go directly off battery.

 

Is the key ON when you checked it for power?
That fuse is powered by the ignition switch.

 

Yes.

 

Would it be possible (maybe easier) to tie a USB port into the lighter plug circuit? Instead of running red into an add-a-circuit fuse tap, and locating a ground point for the black?

 

Are you saying you took the fuses out and flipped them around? If so, that's not necessary, fuses (and similarly, add-a-fuse assemblies) don't care about the direction of the current flow. Also, for a single USB port rated for 3A charging, a 5A fuse should be sufficient.

If you have a multimeter, I would check the potential between the +12V wiring and chassis ground along the route to the USB port. Start at the fuse and work your way to the USB port at each point of access (e.g. any connectors along the way, up to the connector at the USB port itself). Make sure the ignition is in the correct position beforehand.

Off the top of my head: it could be bad wiring, a blown fuse in the add-a-fuse, bad crimps/connections in the add-a-fuse assembly, an inline fuse in the USB port wiring that is missing or blown, or potentially something wrong with the USB assembly itself.

 

The usb I bought is too big to fit where the lighter is…and I already cut a hole and painted the cup holder. So…maybe it’s the ground screw I need to locate? I thought I could just go into any screw on the frame…

 

I know the fuses don’t have an orientation but the add a fuse has a load side and draw side so it matters in location of the fuses. I tested everything off the battery including the usb and none of the fuses are blown. Inline fuse is good too. I mean it’s simple wiring. I wired in my fog lights and my hitch no problems. It could be that I’m not grounding it to a proper screw? I tested it on several and it didn’t power up.

 

Yes, it’s very possible.
I like to use a test light to find a good ground.

You could also use a meter, but not all grounds are equal.
Just because the meter reads 12v or continuity to ground doesn’t mean the ground is good enough once current is applied.

My advice is use a test light. When in doubt test directly from the battery.
I had a bunch of left over wiring from doing light on a trailer. I made extensions with alligator clips just for this purpose.

 

The USB port that fits in a rectangular switch space arrived from STech last night with the three phone/GPS holders I ordered from Scosche, so I just started thinking about placements this afternoon. First thing is trimming a corner off one of the phone holders (all three are alike) so the charging cable plug can be attached from the 12v outlet. I didn't notice any USB ports in the Taco so I need to add that.
I appreciate this thread adding to my knowledge base, since the last auto wiring I did last year was replacing interior lights in a Dodge Sportsman Mini-Winnie, and replacing the old splicing taps that I and one of the old guys at AutoZone remember from the 1970s. I wasn't too sure about those things when they first appeared, but he thought they had those, and managed to find them. I'm glad I bought the pack of 25 instead of 7! I photographed and composed the sale flyer for my friend and may still have it on this PC.
Thank you guys!

 

What add-a-fuse are you using--do you have a link? AFAIK know they are all orientation agnostic, so I'm curious about the one you have. It also may help diagnose you issue.

Where are you grounding?

 

TBH I've never found a bad spot to ground in a vehicle for attaching a power ground (except for places that would create obvious open circuits). In my experience the "quality" of the ground has only ever come into play for signal grounds.

Have you experienced bad grounding locations for power grounds in our trucks (or other vehicles)? Genuinely curious--always open to opportunities to learn from other's experiences.

 

Not in “our” trucks.
But that’s probably because I haven’t done any electrical modifications to a 2nd Gen Tacoma.

On other vehicles I have, but 90% of the time it is usually due to corrosion at the ground location.
That or the object you are grounding to isn’t grounded good.

The worst is usually exterior ground spots, you have to sure the metal CLEAN.

I’d you want to see a “ground issue”
Take a look at the videos below. Craziness

https://youtu.be/Cwxxp9CDTVM
https://youtu.be/n5F0Fy9D6vs

 

Thanks for this entertainment that reminds me of: 1) My college classmate in Missoula, MT, a NoDak bean farmer who had a Fiat X1/9 that started fine when cold, but would not start when the engine was warm, so we drove downtown to celebrate the end of my last final exam in December 1977 at the Ox, watching Norton Buffalo over a couple beers, while the car cooled down. Then drove back to my '66 Rambler wagon and I headed home.
2) When my eldest started driving in Alaska, I had a 1996 Pontiac TransSport SE (2003-2009) with a voltmeter in the dash cluster that would infrequently begin to drop, sometimes back up to normal or continue down to stall. One afternoon, while restocking TP and paper towels in the Harbormaster's Office public restrooms, a stall occupant was talking with his neighbor about a similar problem with a Chevy Lumina. Solution was to slide underneath the (low clearance, wet gravel), loose the wires from the combined alternator-starter, brush and spray clean the connections and tighten things up. Problem solved, which the Chevy dealer in Anchorage could not find with an overnight stay at their shop, a bit nerve-wracking when the voltage drop happens on the Seward Highway during the return trip to Cordova.
I think I'll stick with the 2007 Chevy Mal'bu and 2009 Tacoma, with less complication. (I'll continue with my excuse that I don't use the mobile phone while driving, since I'd rather pay attention to the wildlife and scenery beyond my vehicle, and I'll check and return calls from the recent call list when I'm able to devote my full attention to them.)
Thanks again, Charlie B.

 

Well, there have been similar instances of the same thing happening on the Tacoma.
It seems the 2.7 is usually the one that likes to corrode the wire to the alternator.
And believe it or not, the corrosion travels up the wire a good ways. You have to start pealing the sheathing off. It isn’t just the terminals of the connector.